This invention relates to a device and a method of determining weighing conditions of a dynamic weighing device for weighing an article during its conveyance by a weighing conveyer, for example. Especially, it relates to a device and a method used in such a dynamic weighing device for automatically determining weighing conditions relating to the timing of measurement and the response characteristic value of a filter thereof.
The weighing conditions of the dynamic weighing device include, for example, the timing for measurement of the weight of an article and the response characteristic of a filter for treating weight signals. It is possible to improve the weighing accuracy of the weighing device by adequately setting such weighing conditions in the device.
For example, Japanese opened patent gazette No. H3(91)-282220 discloses an exemplary device used in a weight sorter for determining the timing of measurement. The weight sorter is arranged to weigh articles fed onto a weighing conveyer by a weigher attached to the weighing conveyer and to sort the weighed articles based upon their measured weights. The measured weight is defined as an average of the weight signal generated by each article between two predetermined time points. When the same article is weighed plural times, the measured weight exhibits some variation and the magnitude of variation differs with the positions of two time points. Accordingly, the operator of the weight sorter is required to manually change the positions to record measured data and study the data to determine such positions corresponding to the minimum dispersion thereof before commencing a normal operation.
The weight signal from the weigher is supplied to the measuring means through a filter and, therefore, the measured value and its variation are both subjected to the influence of the response characteristic of the filter, Accordingly, the operator of the sorter is also required to have the response characteristic of the filter made variable and adjust it to determine its value corresponding to the minimum variation of the measured value through a similar procedure to that in determination of the above-mentioned time points.
As described above, in the weight sorter of the above-mentioned Japanese Official gazette, the operator must determine the timing of measurement and response characteristic of the filter before commencing a normal operation in order to assure weighing accuracy. However, this determination procedure includes such a problem in that it requires not only a lot of time and labor, but also a significantly experienced and skilled operator.
Accordingly, an object of this invention is to provide a novel and improved device and method for automatically determining optimum weighing conditions in a dynamic weighing device as described above.